The 16-year-old is hoping to raise $2000, which she said would help fund one major blood cancer research project for a week.
She said she was inspired to take part in the fundraiser by her mum Tracey, who was diagnosed with chronic myeloid leukaemia in 2013.
“I wanted to raise awareness of how common blood cancers are in the world,” she said.
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READ NOW“Most of all I wanted to show support for my mum, who regardless of having a form of leukaemia always supports me in my endeavours and experiences.”
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Keira has already raised $1750 towards her fundraising goal and said she hoped with more fundraising one day there would be a cure.
“It is important to me that money be raised because people in the past, who also raised money by participating in World’s Greatest Shave, allowed for researchers to improve the treatment that my mum receives,” she said.
“This allowed her to survive and live comfortably like many others continuing their days with a blood cancer.
“I want to participate so that in the future the money I raise may allow for other people to survive and continue living in the world my mum has been fortunate to live in.”
Kiera will also donate her hair to make wigs for cancer sufferers.
Ms Macdonald said fortunately her chronic myeloid leukaemia could be managed with effective drug therapies.
She said she was very proud of her daughter for doing something so selfless at such a young age.
“She is a very strong and independent young woman and is doing something to give back to Leukaemia Foundation,” she said.
“She is a real inspiration and a fantastic role model. Actions speak louder than words and shaving her head is a very bold statement.”